Headset with auxiliary input jacks(s) for cell phone and/or other devices

ABSTRACT

Headsets are used in variety of applications to facilitate one- or two-way audio communications between users and/or devices. The present inventor recognized that conventional headsets lack means for successfully integrating more than one audio source, despite their use in proximity to multiple sources of audio signals, such as cell phones, laptops, aircraft radios, and so forth. Accordingly, the present inventors devised one or more devices, circuits, and methods related to connection of at least two audio input signals to a headset. For example, in one embodiment, an active-noise-reduction (ANR) headset includes at least one auxiliary port for connection to an output of at least one device, such as a personal communications, computing, and/or entertainment device. This exemplary headset also includes a primary port for connection to a two-radio or public-address system and circuitry for automatically suppressing or muting the volume of an auxiliary input signal relative to that of a primary input signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 10/624,906, filed Jul. 22, 2003, now U.S. Pat. No.7,215,766 which application claims priority under 35 U.S.C. 119(e) toco-pending and co-owned U.S. provisional application 60/397,888, filedJul. 22, 2002, which applications are incorporated herein by reference.

TECHNICAL FIELD

The present invention concerns headphones or headsets and relatedcircuits and methods.

BACKGROUND

Headsets are used in variety of applications to facilitate one- ortwo-way audio communications between users and/or devices. For example,many aircraft pilots wear headsets to enable them to communicate viatwo-way radio with other aircraft and air-traffic controllers as well asvia a public-address system with passengers. Additionally, some headsetsare worn to facilitate hands-free usage of mobile telephones, whileothers facilitate private listening to devices, such as computers,stereos, disk players, etc.

One problem that the present inventor recognized is that conventionalheadsets lack means for successfully integrating more than one audiosource, despite their proximity to multiple sources of audio signals.Accordingly, there is a need for headsets that facilitate use of morethan one signal source.

SUMMARY

To address this and/or other needs, the present inventors devised one ormore devices, circuits, and methods related to simultaneous connectionof at least two audio input signals to a headset. For example, in oneembodiment, an active-noise-reduction (ANR) headset includes at leastone auxiliary port for connection to an output of at least one device,such as a personal communications, computing, and/or entertainmentdevice. This exemplary headset also includes a primary port forconnection to a two-radio or public-address system and circuitry forautomatically suppressing or muting the volume of an auxiliary inputsignal relative to that of a primary input signal.

Other exemplary features include a headset power supply, a microphone, amicrophone preamplifier, and a device-detection circuit. Thedevice-detection circuit detects connection of the auxiliary port to amicrophone input and couples the power supply to the microphonepreamplifier, enabling it to provide audio signals to the microphoneinput.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an exemplary system 100 corresponding toone or more embodiments of the present invention.

FIG. 2 is a flow chart of an exemplary method of operating one or moreportions of system 100, which corresponds to one or more embodiments ofthe present invention.

FIG. 3 is an electrical schematic of one or more exemplary circuits insystem 100, each corresponding to one or more embodiments of the presentinvention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following detailed description, which references and incorporatesthe attached Figures, describes and illustrates one or more specificembodiments of the invention. These embodiments, offered not to limitbut only to exemplify and teach, are shown and described in sufficientdetail to enable those skilled in the art to implement or practice theinvention. Thus, where appropriate to avoid obscuring the invention, thedescription may omit certain information known to those of skill in theart.

FIG. 1 show an exemplary system 100 incorporating teachings of thepresent invention. Specifically, system 100 includes a primary audiocommunication device 110, a secondary audio communications device 120,and an automatic-noise-reduction (ANR) headset 130.

Primary communications device 110 includes, among other items not shown,a headphone output jack 112 and a microphone jack 114 coupled tointernal circuitry not shown. In the exemplary embodiment, device 110takes the form of a two-way aircraft radio, with headphone jack 112being a 0.250-inch female stereo plug connector and microphone jack 114being a 0.206-inch, female stereo plug connector. In some embodiments,device 110 includes a public-address or intercom capability.

Secondary communications device (or system) 120 includes, among otheritems (not shown), an audio output jack 122 and an external microphonejack 124. In the exemplary embodiment, communications device 120 takesthe form of a cellular telephone, with output jack 122 and microphonejack 124 coupled to interface circuitry (not shown) which supports useof a conventional hands-free mobile-phone headset, which includes amicrophone and an ear-piece (or headphones). (Hands-free headsetstypically include an unbuffered electret microphone that is powered byinterface circuitry (not shown) in the cell phone or other typesecondary device. In the exemplary embodiment, this interface circuitryis not suitable for boom microphones in aviation headsets.) In someother embodiments, device 120 takes the form of a two-way radio, laptopcomputer, or other audio source or audio output device, such as a musicor video player or other personal listening device. In still otherembodiments, device 120 includes or is coupled to an input/output portof a larger multiport distribution network that distributes audiosignals, for example, throughout an airliner.

ANR headset 130 includes, among other things, an earpiece 132, a boommicrophone 134, and a controller 136. Earpiece 132, which each take theexemplary form of circumaural earcup in this embodiment, fits overrespective ear of a user (not shown). However, in other embodiments, theearpiece takes the form of superaural, in-the-ear, or behind-the-eardevices. Specifically, earpiece 132 includes ANR control circuitry 1321,an ANR microphone 1322, an ANR speaker 1323, a non-ANR speaker 1324.

Boom microphone 134 includes a boom 1341 which extends from one ofearpieces 132, and a microphone 1342 positioned at an end of the boom.Other embodiments use other forms of microphones. Earpiece 132 and boommicrophone 134 are both coupled to controller 136.

Controller 136 includes secondary-device detector 1361, a boommicrophone preamplifier 1362, a comm-priority module 1363, a battery box1364, and user controls 1365. In the exemplary embodiment, thecontroller is provided as a box or module separate from the earpieces;however, in some embodiments, all or one or portions of the controllerare incorporated into one or more of the earpieces. For example, someembodiments place one or more of the controller input jacks directly onone of the earpieces.

Secondary-device detector 1361 is coupled to microphone jack 124 ofsecondary communications device 120, microphone preamplifier 1362, andbattery box 1364. Microphone preamplifier 1362, in the exemplaryembodiment, is designed to operate using a 5-10 VDC voltage source and a600-2000 ohm resistor. Comm-priority module 1363 is coupled to headphonejack 122 of primary communications device 110 and to audio output jack122 of the secondary communication. Manual controls 1365 include on-offswitch, left-right volume controls, stereo-mono switch, mode-programmingswitches, and bass and treble controls (all not shown separately.)

In general operation, secondary device detector 1361, which includes anaudio input jack coupled to microphone jack 124 of secondarycommunications device 120, senses or detects connection or activation ofdevice 120 to headset 130 and in response couples power derived frombattery box 1364 to boom microphone preamplifier 1362. Comm-prioritymodule 1363, which is coupled to the headphone jack of the primarycommunications device and to an audio output jack of the secondarycommunication, provides an automatic muting or attenuation function thatreduces the volume or amplitude of an audio or electrical signal derivedfrom the secondary communication device relative to the volume oramplitude of an audio or electrical signal derived from the primarycommunications device. Detector 1361 also senses decoupling ordeactivation of device 120 and in turn decouples battery box 1264 fromboom microphone preamplifier 1362.

More particularly, FIG. 2 shows a flow chart 200 of one or moreexemplary methods of operating system 100, particularly in relation tocontrol module 136. Flow chart 200 includes process blocks 210-280,which are arranged and described serially for clarity. However, two ormore of the blocks, in whole or in part, can be executed in parallel.Additionally, some embodiments may alter the process sequence byomitting or adding one or more blocks or provide different functionalpartitions to achieve analogous results. Moreover, still otherembodiments implement one or more of the blocks using a processor orprogrammable logic device and an electronic, magnetic, or opticalstorage medium bearing machine-executable instructions for execution orfacilitating execution of one or more portions of the exemplary method.Thus, the exemplary process flow applies to software, hardware,firmware, and other implementations beyond those exemplified here.

At block 210, exemplary execution begins with determining whether asecondary device, such as secondary communications device 120, iscoupled to headset 130, or more precisely control module 136. In theexemplary embodiment, this entails using detector 1361 to detect orsense a preamplifier bias signal from secondary communications device120. In some embodiments, the preamplifier bias signal is a 2.5 VDCsignal, which is generally incompatible with the bias signal used inmost aviation-grade ANR headsets. Other embodiments may use the state ofa switch to determine connection of a second device. If thedetermination is that a secondary device is coupled to the headset,execution advances to block 220.

In block 220, detector 1361 couples power derived from battery box 1364to microphone preamplifier 1362, thereby enabling the headset toself-power its boom microphone rather than relying on power from theprimary communications device. This self-powering feature allows one touse the headset with the secondary communications device independent ofany connection to the primary communications device. One benefit of thisfeature is that it allows the secondary device to be used in a noisyenvironment with no other electronics or power beyond the headsetitself. Execution of the exemplary method continues at block 230.

Block 230 entails headset 130 receiving audio signals from one or theother or both of the primary and the secondary communications devices110 and 120. In the exemplary embodiment, these audio signals arereceived at comm-priority module 1363 via headphone jack 112 and/oraudio output 122. Execution then proceeds to block 240.

Block 240 entails determining whether to alter the relative amplitude ofthe primary and secondary audio signals. In the exemplary embodiment,this entails comparing the primary audio signal (more precisely thevoltage at headphone jack 112) to a threshold voltage. If the comparisonindicates that the primary audio signal is greater than the thresholdvoltage, execution advances to block 250; otherwise execution branchesto block 260.

Block 250 entails altering the relative amplitude of the primary andsecondary audio signals. In the exemplary embodiment, this alterationentails reducing the amplitude (or volume) of the secondary audio signalrelative to that of the primary audio signal. Some embodiments mayincrease the amplitude or volume of the primary audio signal to begreater than that of secondary audio signal. Some embodiments mayadditionally output a notification signal, such as high-pitched tone orbeep, to indicate presence of an primary audio signal in excess of thethreshold.

Block 260 entails mixing the primary and secondary audio signals. In theexemplary embodiment, this mixing entails mixing the primary audiosignal, or more precisely any voltage present on headphone jack 112 withthe reduced or unreduced secondary audio signal.

Block 270 entails outputting the mixed primary and secondary audiosignals to one or both of earpieces 132. In th exemplary embodiment, themixed signals are output to speaker 1324 and to ANR circuitry 1321. Someembodiments, however, may omit or bypass the ANR circuitry. Executionthen returns back to block 210.

Block 210 determines whether there is still a secondary device coupledto the headset. If the determination is that a device is still coupledto the headset, execution continues to block 220, as previouslydescribed. However, if the determination is that there is no secondarydevice (or that the secondary device has been deactivated, for example,as evidenced by failure to preceive a microphone bias voltage from thedevice), then execution advances to block 280, which entails decouplingof the headset battery from the boom microphone preamplifier to conservebattery power.

FIG. 3 shows circuitry 300, which includes a detector circuit 310 thatrepresents an exemplary implementation of secondary-device detector 1361and a comm-priority circuit 320 that represents an exemplaryimplementation of comm-priority module 1363. In the figure, incomingsignals from the secondary device are received at secondary inputs Aux_Rand Aux_L, and incoming signals from the primary device are received atCOM_AUD TIP and COM_AUD GND. Battery terminals (shown in the lowerlefthand corner) are labeled Bat+ and Bat−.

Detector circuit 310 detects the presence of an external bias signal atan audio input jack (denoted cell_mic in the figure) via a transistorQ6, which turns on the current source comprising a transistor Q10.Activation of the current source provides a bias current for the boommicrophone preamplifier. The current source has a compliance of over 10VDC for undistorted communications at high-sound pressures. Notably,this implementation does not interfere with normal operation of the boommicrophone preamplifier, if it is connected to a radio or intercom biascircuit because it is a current source realizing a high Thevininequivalent impedance. Although not preferred, some embodiments may use asource with a low Thevinin equivalent impedance.

Comm-priority circuit 320 treats the Com_L input as the primary input tothe headset and compares this signal to a threshold voltage viacomparitor circuitry that includes operational amplifier U1B. If thesignal at the Com_L input exceeds the trigger threshold (set byresistors R1 and R2, voltage V+, and processor output pin 11), then theoutput of operational amplifier U1B output goes high, saturatingtransistor Q8 and causing this transistor to rapidly discharge capacitorC1. In response to this discharge, operational amplifier U1C produces alow voltage at its output, which is coupled to a pulse-width-modulation(PWM) circuit comprising oscillator U4 and PWM comparitor U3.

In turn, the PWM circuit reduces the duty cycle of its output signal.This output signals controls analog switch U11 (4053), which is part ofa chopping circuit, causing it to attenuate the auxiliary inputs Aux_Land Aux_R. U1a and U1d denote summing amplifiers that sum or mix theprimary and secondary inputs, and also provide a reconstruction filterfor the chopped signal. The output of summing amplifiers U1a and U1d arethen passed up to the earpieces for transduction into acoustic signals.

When the primary audio input stops exceeding the trigger threshold,capacitor C1 slowly starts to charge up via resistor R3, thus increasingthe duty cycle of the signal output from the PWM circuit and the gainlevel of the secondary audio input. The exemplary embodiment increasesthis gain linearly until it reaches its original level. (Non-linearrestoration of the secondary signal is also feasible.) Microprocessor U5is programmable via control inputs Control1 and Control2 to disablecommunications priority by setting processor output pin 11 to a highlogic state and thereby moving the trigger threshold for initiatingattenuation of the secondary input to a high value.

Other implementations could assign priority to the secondary inputs orallow the user to select which inputs have priority. The comm-priorityfunctionality is selectable and controlled through microprocessor U5using a combination of pushes of a button on a separate control module,such as module 136. Other embodiments place this control with controlson one or more of the earcups, the bridge between the earcups, or otherconvenient location.

Conclusion

The embodiments described above are intended only to illustrate andteach one or more ways of practicing or implementing the presentinvention, not to restrict its breadth or scope. The actual scope of theinvention, which encompasses all ways of practicing or implementing theconcepts of the invention, is defined by the following claims and theirequivalents.

1. A headset or headset assembly comprising: a boom microphone; a boommicrophone preamplifier coupled to the boom microphone; first inputmeans for electrically coupling the headset to receive audio signalsfrom a first source, wherein the first source includes a two-wayaircraft radio; second input means for electrically coupling the headsetto receive audio signals from a second source, wherein the second sourceincludes a cellular telephone having headset interface circuitry that isincompatible with the boom microphone preamplifier; and circuitry forallowing proper interfacing of the boom microphone preamplifier to boththe two-way aircraft radio and the cellular telephone.
 2. The headset ofclaim 1, further comprising: circuitry for comparing received audiosignals from the first source to a reference; circuitry for attenuatingthe received audio signals from the second source when the receivedaudio signals from the first source exceed a reference level; a mixerfor mixing and outputting signals based on the audio signals receivedfrom the first and second sources; automatic noise reduction circuitrycoupled to receive the signals output from the mixer.
 3. The headset ofclaim 1, further comprising: a pair of battery terminals for connectionto at least one battery; and means for powering the boom microphonepreamplifier via the first source or via the pair of battery terminals.4. The headset of claim 3, further comprising circuitry for detectingpresence of a 2.5 VDC bias signal from the cellular telephone.
 5. Theheadset of claim 4, wherein the circuitry for detecting presence of the2.5 VDC bias signal activates a current source which provides a biascurrent to the boom microphone preamplifier.
 6. The headset of claim 1,wherein the circuitry for allowing proper interfacing of the boommicrophone preamplifier to both the two-way aircraft radio and thecellular telephone, comprises: means for allowing proper interfacing ofthe boom microphone preamplifier to both the two-way aircraft radio andthe cellular telephone.
 7. An automatic noise reduction (ANR) headsetcomprising: means for connecting the ANR headset to simultaneouslyreceive communication signals from a two-way aircraft radio and from acellular telephone; a pair of battery terminals for connection to atleast one battery; a boom microphone coupled to a boom microphonepreamplifier; and means for coupling the boom microphone preamplifier toreceive power via connection to either the aircraft two-way radio or thepair of battery terminals.
 8. The ANR headset of claim 7, wherein thecellular telephone is configured to provide a 2.5 VDC bias and the boommicrophone preamplifier is configured to operate in a 5-10 VDC range.